SPDL1 and non-small cell lung carcinoma: The subgroup meta-analysis, which pooled data for OS from five studies, including 542 patients affected by NSCLC, indicated that a higher concentration of sPD-L1 in the blood of these patients was significantly associated with worse survival, with an HR = 1.81 (95%CI: 1.09–3.00, p = 0.02, I2 = 83%; Figure 4).